Fitness questions and answers for January 31, 2005

Got a question about fitness, training, recovery from injury or a related subject? Drop us a line at...

Form & Fitness Q & A

Got a question about fitness, training, recovery from injury or a related subject? Drop us a line at fitness@cyclingnews.com. Please include as much information about yourself as possible, including your age, sex, and type of racing or riding. Due to the volume of questions we receive, we regret that we are unable to answer them all.

Carrie Cheadle, MA (www.carriecheadle.com) is a Sports Psychology consultant who has dedicated her career to helping athletes of all ages and abilities perform to their potential. Carrie specialises in working with cyclists, in disciplines ranging from track racing to mountain biking. She holds a bachelors degree in Psychology from Sonoma State University as well as a masters degree in Sport Psychology from John F. Kennedy University.

Dave Palese (www.davepalese.com) is a USA Cycling licensed coach and masters' class road racer with 16 years' race experience. He coaches racers and riders of all abilities from his home in southern Maine, USA, where he lives with his wife Sheryl, daughter Molly, and two cats, Miranda and Mu-Mu.

Kelby Bethards, MD received a Bachelor of Science in Electrical Engineering from Iowa State University (1994) before obtaining an M.D. from the University of Iowa College of Medicine in 2000. Has been a racing cyclist 'on and off' for 20 years, and when time allows, he races Cat 3 and 35+. He is a team physician for two local Ft Collins, CO, teams, and currently works Family Practice in multiple settings: rural, urgent care, inpatient and the like.

Fiona Lockhart (www.trainright.com) is a USA Cycling Expert Coach, and holds certifications from USA Weightlifting (Sports Performance Coach), the National Strength and Conditioning Association (Certified Strength and Conditioning Coach), and the National Academy for Sports Nutrition (Primary Sports Nutritionist). She is the Sports Science Editor for Carmichael Training Systems, and has been working in the strength and conditioning and endurance sports fields for over 10 years; she's also a competitive mountain biker.

Eddie Monnier (www.velo-fit.com) is a USA Cycling certified Elite Coach and a Category II racer. He holds undergraduate degrees in anthropology (with departmental honors) and philosophy from Emory University and an MBA from The Wharton School of Business.

Eddie is a proponent of training with power. He coaches cyclists (track, road and mountain bike) of all abilities and with wide ranging goals (with and without power meters). He uses internet tools to coach riders from any geography.

David Fleckenstein, MPT (www.physiopt.com) is a physical therapist practicing in Boise, ID. His clients have included World and U.S. champions, Olympic athletes and numerous professional athletes. He received his B.S. in Biology/Genetics from Penn State and his Master's degree in Physical Therapy from Emory University. He specializes in manual medicine treatment and specific retraining of spine and joint stabilization musculature. He is a former Cat I road racer and Expert mountain biker.

Since 1986 Steve Hogg (www.cyclefitcentre.com) has owned and operated Pedal Pushers, a cycle shop specialising in rider positioning and custom bicycles. In that time he has positioned riders from all cycling disciplines and of all levels of ability with every concievable cycling problem.They include World and National champions at one end of the performance spectrum to amputees and people with disabilities at the other end.

Current riders that Steve has positioned include Davitamon-Lotto's Nick Gates, Discovery's Hayden Roulston, National Road Series champion, Jessica Ridder and National and State Time Trial champion, Peter Milostic.

Pamela Hinton has a bachelor's degree in Molecular Biology and a doctoral degree in Nutritional Sciences, both from the University of Wisconsin-Madison. She did postdoctoral training at Cornell University and is now an assistant professor of Nutritional Sciences at the University of Missouri-Columbia where she studies the effects of iron deficiency on adaptations to endurance training and the consequences of exercise-associated changes in menstrual function on bone health.

Pam was an All-American in track while at the UW. She started cycling competitively in 2003 and is the defending Missouri State Road Champion. Pam writes a nutrition column for Giana Roberge's Team Speed Queen Newsletter.

Dario Fredrick (www.wholeathlete.com) is an exercise physiologist and head coach for Whole Athlete™. He is a former category 1 & semi-pro MTB racer. Dario holds a masters degree in exercise science and a bachelors in sport psychology.

Scott Saifer (www.wenzelcoaching.com) has a Masters Degree in exercise physiology and sports psychology and has personally coached over 300 athletes of all levels in his 10 years of coaching with Wenzel Coaching.

Kendra Wenzel (www.wenzelcoaching.com) is a head coach with Wenzel Coaching with 17 years of racing and coaching experience and is coauthor of the book Bike Racing 101.

Steve Owens (www.coloradopremiertraining.com) is a USA Cycling certified coach, exercise physiologist and owner of Colorado Premier Training. Steve has worked with both the United States Olympic Committee and Guatemalan Olympic Committee as an Exercise Physiologist. He holds a B.S. in Exercise & Sports Science and currently works with multiple national champions, professionals and World Cup level cyclists.

Through his highly customized online training format, Steve and his handpicked team of coaches at Colorado Premier Training work with cyclists and multisport athletes around the world.

Brett Aitken (www.cycle2max.com) is a Sydney Olympic gold medalist. Born in Adelaide, Australia in 1971, Brett got into cycling through the cult sport of cycle speedway before crossing over into road and track racing. Since winning Olympic gold in the Madison with Scott McGrory, Brett has been working on his coaching business and his www.cycle2max.com website.

Richard Stern (www.cyclecoach.com) is Head Coach of Richard Stern Training, a Level 3 Coach with the Association of British Cycling Coaches, a Sports Scientist, and a writer. He has been professionally coaching cyclists and triathletes since 1998 at all levels from professional to recreational. He is a leading expert in coaching with power output and all power meters. Richard has been a competitive cyclist for 20 years

Andy Bloomer (www.cyclecoach.com) is an Associate Coach and sport scientist with Richard Stern Training. He is a member of the Association of British Cycling Coaches (ABCC) and a member of the British Association of Sport and Exercise Sciences (BASES). In his role as Exercise Physiologist at Staffordshire University Sports Performance Centre, he has conducted physiological testing and offered training and coaching advice to athletes from all sports for the past 4 years. Andy has been a competitive cyclist for many years.

Michael Smartt (www.cyclecoach.com) is an Associate Coach with Richard Stern Training. He holds a Masters degree in exercise physiology and is USA Cycling Expert Coach. Michael has been a competitive cyclist for over 10 years and has experience coaching road and off-road cyclists, triathletes and Paralympians.

Kim Morrow (www.elitefitcoach.com) has competed as a Professional Cyclist and Triathlete, is a certified USA Cycling Elite Coach, a 4-time U.S. Masters National Road Race Champion, and a Fitness Professional.

Her coaching group, eliteFITcoach, is based out of the Southeastern United States, although they coach athletes across North America. Kim also owns MyEnduranceCoach.com, a resource for cyclists, multisport athletes & endurance coaches around the globe, specializing in helping cycling and multisport athletes find a coach.

Advice presented in Cyclingnews' fitness pages is provided for educational purposes only and is not intended to be specific advice for individual athletes. If you follow the educational information found on Cyclingnews, you do so at your own risk. You should consult with your physician before beginning any exercise program.

Lower back pain
Heart Rate
Drop in max HR
Cleat position question
Low Heart rate during training
Bone density
Vitamin questions

Lower back pain

I've been struggling for a couple of years trying to remedy a major pain in my lower left back, which occurs about 30 minutes into a ride. I read your replies on related matters in the Fitness section and as a result purchased 'Overcoming Neck and Back Pain'. Based on reading the book I learnt that my left leg is about 1cm longer than my right, and so I installed 1/2cm heel lifts in my walking shoes, and 1/2cm cleat shims in my cycling shoes. I also learnt that the hip flexors, hips and hamstring muscles in both my legs have poor flexibility. I hoped to improve this as part of carrying out the set of stretching exercises specifically recommended for lower back problems twice a week. Also, from reading the book it sounded like stretching my QL muscles could be a cure to my problem, so I made sure I stretched these also. However, six months later, none of the above action showed results.

I've also tried attending Pilates classes at the local leisure centre and working through the exercises in the Pilates book you recommended, 'Pilates for Dummies'. Finally, I recently saw a Chiropractor for two sessions. He was adamant the problem was due to a stiff L4 vertebrae, and so spent time trying to mobilize it. However, again, these actions showed no results.

I'm not sure whether it's related, but my pedal stroke has always caused significant movement in my upper body (to the point of being almost out of control at highish cadences - around 160). I'm convinced my saddle isn't too high as I have a bend in both of my legs under load, and I don't get any pulling at the top of my hamstrings after a long hilly ride. I do have a small mpg video I can send you of me from behind on my turbo if this would help diagnosis and you'd be willing to look at it.

With the above in mind, I was wondering if you had any advice you could give me? I realize I may not have given you all the information you need, or that it may be impossible to properly diagnose remotely, but I'm getting despondent and any advice you could give me that would help me make progress would be hugely appreciated. I'm not sure if they have any bearing, but I've put into practice the instructions you've given to others on fitting and I tend to have a natural tendency to grind gears.

Neil

Steve Hogg replies

G'day Neil,

Re - the video thing. I have been experimenting with this with a number of 'test pilots' in the States and am far from happy with the results. The basic problem is gross problems are obvious but no video medium that I have seen to date has enough resolution to show the level of fine detail I need to get the results that I am used to getting in the flesh. At some future stage, if the technology improves to the point where it is like being there, I will give it another try. I think that time is a long way off.
I don't suppose you feel a pressing need for an Antipodean holiday [I am
half-joking!]

Still, I am happy to try and help. Let's work through what you have said sequentially.

1. No improvement in flexibility. Do you mean that there has been no improvement in your range of movement or that simply no improvement to the degree of discomfort you feel on the bike?
2. With the Pilates and chiropractor, again, do you mean no improvement on bike or simply no improvement at all?
3.The upper body movement while pedalling is usually a result of total lack of flexibility in the hips and pelvis. When the pelvis is unstable on the seat, the effects of that pelvic movement naturally flow upward and outward. The tendency to push big gears is often a corollary of this in that slower rpms place less demand on pelvis stability because a lesser degree of muscular co ordination is required. Now some info I need from you:

a) Set your bike up on an indoor trainer and make sure that it is dead level between axle centres. You will need a trusted observer with at least half a brain. With the observer standing above and behind you, do you drop or rotate either hip forward?
b) If so and you will be, which one?
c) Or, alternately, if both are doing this, which is more pronounced?
d) Does your torso appear twisted towards one side from behind.
e) Do you thrust either shoulder forward further than the other and if so, which one?
f) When you are on the drop bars does your lumbar spine [lower back] face forwards somewhat, or is it relatively upright, or does it lean backwards?
g) What size and brand of shoes are you using, and what pedal system are you using?

If you can accurately give me that information, we will proceed from there.

Heart Rate

I am a 35-year-old rider who has been regularly riding a bike for about a decade, and have been experimenting on heart rate monitor training. When I started riding seriously a few years back and started to use a heart rate monitor, it did wonders for me. I have improved from being the novice in the group to a very good cat 5 local rider.

However, I've always read on all the training books and magazines that the most common way to determine your max HR is 220 minus your age. When I follow that formula and follow the recommended training efforts in books and magazines my bike barely moves. Meaning that 60% of my max hr is 110 bps. This is my HR the moment I hop on the bike without even starting to pedal. When I to out to train I increase the max to about 195 to be able to at least so that my bike will at least move if the training calls for 60% effort. Am I putting myself in any kind of danger by doing this?
I understand that the training books and magazines recommend these numbers based upon an "average" person. But do they mean that average person who does not exercise or the average athlete?

I am planning to do a few local races this year, and I have never had a coach before but have done ok. I really want to improve without spending the money for a professional trainer. Please enlighten me on the heart rate monitor issues so I can base my training on the correct numbers.

Raymond de Leon

Scott Saifer replies

Hi Raymond,

I recently published and article in ROAD magazine on just this topic. The 220-age formula is frequently off by as much as 10-15 beats for a given rider and doesn't even hit the average very well for trained riders. 210 - age/2 does a better job of approximating the average for trained cyclists, but is still off by 10-15 beats for many riders. The only way to set up heart rate training zones for a serious cyclist is to actually test one's own maximum and ventilatory threshold. If you've been racing, the highest heart rate you've seen during an all out effort is likely to be your maximum or within a few beats.

Drop in max HR

Hi there,

Something peculiar has happened to me and I would be grateful if you could clarify. I am 38-years-old and have been training steadily about 10 hours cycling per week since September last year. It's been almost exclusively low intensity -ie- Zone-2 type work, and all indoor on a turbo.

When I measured my max HR early last year it was 194 and I planned my workouts accordingly. I was able to reach 194 throughout the year. I am now starting to plan specific workouts for this spring and I have made three attempts to measure my max HR and I have not been able to exceed 175 - a drop of 19 points since last year.

I feel stronger than at the same time last year and my condition is better vis a vis my cycling team mates than it was last year. I am therefore curious why my max HR has dropped so much. I would also add that last year I was running a HR of about 135 during easy rides while now my easy rides at the same effort are 125 or less. Most of my work since last fall has been indoors on a turbo, where I have been able to keep a very steady effort throughout my rides.

Should I continue to try to force my max HR up further or should I set my work out zones based on my 'new' max HR of 175? I'd be grateful for your assistance.

Fred Oyen

Jon Heidemann replies

Hello Fred,

I would continue to consider your max HR to be 194. It's possible it has lowered, but even so, by only a few beats. A 20-beat drop in max HR in less than a year is very unusual. However, for zoned training quantifications, I feel that is best determined from your lactate threshold point. There are a number of ways to determine LT, the best of which is in a laboratory setting. I encourage you to investigate LT determination. I'm certain the forum has addressed LT determination in the past, so look into the archives.

Unless you are able to get specific lab testing to pinpoint the exact reason why you haven't seen or replicated your HR max is difficult. However, I can tell you that there are several combined reasons why your heart rate "behaviour" may have changed over the past few months.

You most likely have experienced an increased blood volume shift from the consistent training and training type (z2 3) you have been doing. Essentially, this means the total volume of the blood in your body has increased, resulting in increased oxygen and energy delivery throughout your system. So, for every "beat" of your heart, you are delivering an increased amount of oxygen and energy. If this were to occur, your heart rate would be lower for the same effort.

Also, your body most likely has become more efficient. Loss of fat mass and increased vascular density in muscles will ensure a more efficient system. Once again, this requires your heart to do less work for the same effort level.

There could be a few more reasons, but I think the previous two are the most plausible.

Now, as to why you haven't seen a max HR in recent months. One thing I noted in your question was that you have been doing a majority of your riding on the indoor trainer. From personal experience and having coached many athletes, I know getting a true HR max on the trainer is very difficult. And it seems the more time spent on the trainer, the harder it is to reach. It can be done, but, not always. The best (and easiest) opportunity to get a max HR is at the end of a rest week, on a very difficult group ride or race where your limits are often pushed. The added external stimulation that other riders give you will often allow you to push yourself harder than doing so on your own. There are max HR testing protocols you could follow (other forum members may even mention one), but even so, you are required to utilize your own motivation to push yourself to that upper end of efforts.

Good luck and happy riding.

Cleat position question

I recently started using a new pair of shoes, and located the cleats using the guidance you have given over the last several instalments of the Fitness Q&A.

One problem that I did have was locating the ball of my foot exactly within the shoe because of the thick leather that they are made from (much thicker than my old pair). I was pleasantly surprised to find that the location you recommend is almost exactly the location I have been using, as I notice almost no difference in the "feel" when I pedal. I did have one question, however. Because of the problem I had locating the ball of my foot, I believe that my right foot is slightly off from my old position - I am having a tightness in my right quad and the top of my right calf. This seems to indicate to me that my foot is slightly behind where it was in my previous shoe. Would you concur?

Steve Hill

Atlanta, GA

Steve Hogg Replies

G'day Steve,

It is hard to answer with any certainty. If the cleat is too far back and you are over extending slightly it would be possible to have the symptoms that you have developed. Equally, if the cleat is slightly too far forward, there will be more strain in all parts of the pedalling chain above the foot.

Put your shoes on and using thumb and index finger, locate the furthest forward and furthest rearward parts of the first metatarsal joint. Simply put a marker pen dot halfway between thumb and index finger and you will be very close. Place this mark on the side of the shoe. I imagine you know what angle your feet sit on the pedals under load. Remove the shoes from your feet and fit one shoe at a time into the pedals, level the shoe and find where that marker pen dot is in relation to the pedal axle centre.
Once you have done this, ride for a couple of rides and re evaluate. Does one foot feel better than the other?
If so, move the other cleat in the direction that seems appropriate - 2mm at a time is enough to make a noticeable difference. If you are adjusting the cleat in the wrong direction, it will become obvious fairly quickly and you can then remedy.

The only common trap is that when levelling the shoe to check cleat position, make sure that you are levelling the shoe between where the shoe joins the upper underneath the heel and where the shoe joins the upper under the ball of the foot.
If you need further info on this, just yell.

Low Heart rate during training

For the past four weeks or so of my base training (six in total thus far) my average pulse has declined slowly from day to day. Obviously I'm not doing any hard efforts, but even when cruising at a brisk pace, my HR remains low.

Normally a low exercising pulse would be a sign of illness, but I feel as strong as ever, and though I don't have a wattage meter, and all of my rides are on a trainer or rollers (lovely New England winters) I'm able to spin a gear or two larger than six weeks ago with little effort. Most importantly, my morning pulse has declined as well, so over-training isn't a problem. My morning pulse has dropped from 38-39 at the beginning of base training, to now 34-37. I feel good while training, but it's unnerving to see my pulse in the mid 140's to 130's, when this time last year it was in the 150's.

One possible explanation I came up with is the fact that I suffered from iron-deficient anaemia last year, which was discovered after lacklustre results in the junior world cup in Quebec. This came after having completed a great spring season.

If it helps, I'm a 17 y/o male, 6'1'', and 138 lbs. I have been training 2-3 hours five times a week (on the rollers, no hard intervals, avg. approx 13-15 hours per week), plus as much XC skiing as my schedule permits, which is usually 1.5 hours one or two days week. Two days are dedicated to recovery rides and core strength, so again I don't feel over-trained. What's your take, and should I be concerned?

Evan

Scott Saifer Replies

Hi Evan,

If your speed or power are the same or higher and your heart rate is lower, that is generally a sign of improving aerobic fitness.
Correcting anaemia would also let you do the same work with a lower heart rate, so in general lower heart rate during training is not a bad thing, but in fact a good thing.
You didn't mention what happens if you try to go hard. If you try to go hard and your heart rate won't rise much above your comfortable cruising level, then you have a problem. If it rises normally when you make a hard effort, you have nothing to worry about.

Bone density

Good day

I am 42-year-old, 5'9", 168 lbs, and ride 340 to 350 days per year for the past 12 years

Recently (last week) I have been diagnosed with two broken bones in my right foot. The action that sent me to the hospital was stepping off a curb (fairly low impact). The assumption is that the bones were broken over the summer (with failure last week). I believe breaking of bones in a cyclist's foot from pedalling is rare, but how is low bone density, weakness, associated with cycling. My diet has also included very little dairy over the past year. Do cyclists often have bone density problems? Thanks.

Charlie Tarver

Pam Hinton Replies

Hi Charlie,

Osteoporosis typically brings to mind an elderly woman. We don't often consider the possibility that younger people, especially physically active males, could be at risk for low bone density. But, you're right in suspecting that your fracture may be a result of years spent off your feet and on your bike. Bone density is affected by genetics, nutritional and hormonal status, and the mechanical stress exerted on the bones. There's not much you can do about your genes, so let's talk about the other factors.

Many nutrients are needed for bone health, but calcium and vitamin D are the key players. With inadequate dietary calcium, the body has to use the calcium that is stored in the mineral matrix of the bones to keep blood calcium levels stable. Over time, insufficient calcium in the diet can lead to a significant loss of bone mineral, making the bones less dense and, thus, more fragile. Vitamin D is critical for calcium absorption from the intestine. The body can make vitamin D from cholesterol; the process requires skin exposure to ultraviolet (sun) light. So individuals who live in northern latitudes are at greater risk for vitamin D deficiency. Good food sources of vitamin D are milk and other dairy products, fatty fish and liver.

Growth and maintenance of bone are also dependent on hormones. The sex steroids (estrogens and testosterone) and growth hormone stimulate bone formation. The rapid loss of bone that occurs in estrogen-deficient states (e.g., menopause, anorexia nervosa, lactation), illustrates the importance of this hormone in women. During the first 5-7 seven years after menopause, women may lose up to 20% of their bone mass. For men, part of the normal aging process is a gradual reduction in testosterone and growth hormone production, which may contribute to lower bone mineral density. For both men and women, a chronic energy deficit causes a reduction in the sex steroids. For example, females with anorexia nervosa experience lack of menstrual cycles due to inadequate estrogen production. Athletes who severely restrict their energy intake in order to lose weight or body fat may be in negative energy balance. For women, the lower estrogen production may result in irregular or absent menstrual cycles. Other than a reduction in sex drive, there are no overt signs of low testosterone levels in males.

Mechanical stress on bone is critical to maintaining bone mass. Body weight is one source of mechanical stress on the skeleton. The significance of weight on bones is illustrated by the dramatic loss of bone mass that occurs with weightlessness (e.g., during space travel or bed rest). Another source of stress on bones is the force exerted by muscle contraction. For example, the bone density of a tennis player's dominant arm is significantly greater than the non-dominant arm. In general, physical activity increases bone density because of the increased stress on the skeleton. The type, frequency, and duration of exercise all determine the effect of the activity on bone. Dynamic exercise has a greater positive effect on bone mass than static exercise because it provides a larger stimulus for bone growth. Fluid shifts within the bone cells are the signal for bone deposition. High-impact activities like running and jumping cause greater fluid shifts than low-impact activities like walking or weight training. Bone can become unresponsive to mechanical loading so it is more effective to perform activities more often for a shorter duration than to do fewer reps for a longer time period.

Having said all of that, it should be obvious that non-weight bearing activities (e.g., swimming, cycling) do not increase bone density. A recent study of master cyclists, who had been riding for at least 10 years, found that the older cyclists had lower bone density of the spine and hip than young adult cyclist and age-matched controls who were moderately active. The cumulative effect of hours spent with the skeleton unloaded is the likely cause of the lower bone mineral density in the masters, but not young adult, cyclists.

I recommend that you increase your calcium intake to 1000-1200 mg per day. Dairy products have about 300 mg per serving. Other foods, like breakfast cereals and orange juice, are sometimes supplemented with calcium, so check the food labels. You should also incorporate weight-bearing activity into your training program. Running, jumping rope, and plyometric exercises, would all be good options. Take care.

Vitamin questions

I have a few vitamin supplement questions - what ingredients and levels should a cyclist (or any endurance athlete) look for in a multivitamin? What should you look to avoid, if anything? What is the best time of day to take a vitamin supplement? My current multi-vitamin has a suggested dosage of two per day, and should I take both of these at the same time, or one every 12 hours? Thanks.

Ben

NC

Pam Hinton Replies

Hi Ben,

Athletes often believe that their vitamin and mineral needs are significantly higher than the average non-athlete and that if they consume only the RDA they will not get the amounts they need. What athletes do not realize is that RDAs are set above the mean requirement for the general population, so that there is a "safety factor" built into them. For example, take the RDA for iron for women 19-50 years of age, 18 mg per day, and compare it to the mean requirement, 8 mg per day. You can see just how large the margin of error is. Yes, athletes may require more of some nutrients than non-athletes, but the increment is small relative to the safety factor. My point is that athletes will meet their nutrient needs if they consume the RDAs, which can easily be met by eating a well-balanced diet.

Of course, athletes should eat a balanced diet of whole grains, lean meat and dairy products, fresh fruits and vegetables. But, if they want some insurance against suboptimal intakes, their best bet is to take an over-the-counter multivitamin that provides no more than the RDA. The best time to take a vitamin supplement is with a meal. You will absorb more of the vitamins if the supplement is taken with food. This is because there are substances in food that enhance absorption. For example, the absorption of the fat-soluble vitamins is significantly increased in the presence of dietary fat. If your supplement regimen dictates taking two pills, then taking one with breakfast and the other with dinner would be more effective than taking them together.

Vitamin excesses can be just as dangerous as vitamin deficiencies. The potential for toxicity is greater for fat-soluble vitamins compared to water-soluble vitamins because the excess is stored and can accumulate to toxic levels over time. For example, consuming just 3-4 times the RDA for vitamin A over time can result in toxicity symptoms: loss of appetite, hair loss, bone and muscle pain. Excess vitamin D causes calcification of the organs, high blood pressure, and kidney dysfunction. Large doses of water-soluble vitamins can also be harmful. For example, vitamin C normally acts as an antioxidant, preventing damage to the cell membrane by reacting with harmful molecules. However, at high levels, vitamin C can act as a pro-oxidant, reacting with iron or copper to generate compounds that can cause cell damage. Megadoses of vitamin B6 can cause degeneration of nerves, resulting in unsteady gait, numbness in the extremities and impaired tendon reflexes.

In addition to vitamins, some individuals may benefit from taking a daily supplement with minerals. However, taking a mineral supplement when you don't need it can do more harm than good. For example, iron is toxic, causing organ damage when it is present in high amounts. Because the body has no way of excreting excess iron, it is possible to overdose on iron supplements. Unless you are deficient in a particular nutrient, single-nutrient supplements are best avoided. This is because single-nutrient supplements often provide more than the RDA and taking a large amount in a single dose is likely to interfere with the absorption of other nutrients. This is especially true of the minerals. Iron and zinc are mutual antagonists, as are calcium and magnesium.

So, aim to meet your nutrient needs by eating whole foods rather than relying on supplements. You are less likely to get too much a good thing that way. Plus food contains compounds that are not necessary for life, but that promote health. For example, lycopene is a substance found in tomatoes that has antioxidant activity and reduces the risk of prostate cancer.

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